--- old/src/java.base/unix/native/libnet/PlainDatagramSocketImpl.c 2019-03-14 10:36:26.989903159 +0000 +++ new/src/java.base/unix/native/libnet/PlainDatagramSocketImpl.c 2019-03-14 10:36:26.737903167 +0000 @@ -917,7 +917,7 @@ /* Disable IPV6_V6ONLY to ensure dual-socket support */ if (domain == AF_INET6) { - arg = 0; + arg = 1; // ENABLE if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, (char*)&arg, sizeof(int)) < 0) { NET_ThrowNew(env, errno, "cannot set IPPROTO_IPV6");